Java tutorial
/* * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package jdk.nashorn.api.scripting; import java.util.Collection; import java.util.Collections; import java.util.Objects; import java.util.Set; import jdk.nashorn.internal.runtime.JSONListAdapter; import jdk.nashorn.internal.runtime.JSType; /** * This is the base class for nashorn ScriptObjectMirror class. * * This class can also be subclassed by an arbitrary Java class. Nashorn will * treat objects of such classes just like nashorn script objects. Usual nashorn * operations like obj[i], obj.foo, obj.func(), delete obj.foo will be delegated * to appropriate method call of this class. * * @since 1.8u40 */ @jdk.Exported public abstract class AbstractJSObject implements JSObject { /** * The default constructor. */ public AbstractJSObject() { } /** * @implSpec This implementation always throws UnsupportedOperationException */ @Override public Object call(final Object thiz, final Object... args) { throw new UnsupportedOperationException("call"); } /** * @implSpec This implementation always throws UnsupportedOperationException */ @Override public Object newObject(final Object... args) { throw new UnsupportedOperationException("newObject"); } /** * @implSpec This imlementation always throws UnsupportedOperationException */ @Override public Object eval(final String s) { throw new UnsupportedOperationException("eval"); } /** * @implSpec This implementation always returns null */ @Override public Object getMember(final String name) { Objects.requireNonNull(name); return null; } /** * @implSpec This implementation always returns null */ @Override public Object getSlot(final int index) { return null; } /** * @implSpec This implementation always returns false */ @Override public boolean hasMember(final String name) { Objects.requireNonNull(name); return false; } /** * @implSpec This implementation always returns false */ @Override public boolean hasSlot(final int slot) { return false; } /** * @implSpec This implementation is a no-op */ @Override public void removeMember(final String name) { Objects.requireNonNull(name); //empty } /** * @implSpec This implementation is a no-op */ @Override public void setMember(final String name, final Object value) { Objects.requireNonNull(name); //empty } /** * @implSpec This implementation is a no-op */ @Override public void setSlot(final int index, final Object value) { //empty } // property and value iteration /** * @implSpec This implementation returns empty set */ @Override public Set<String> keySet() { return Collections.emptySet(); } /** * @implSpec This implementation returns empty set */ @Override public Collection<Object> values() { return Collections.emptySet(); } // JavaScript instanceof check /** * @implSpec This implementation always returns false */ @Override public boolean isInstance(final Object instance) { return false; } @Override public boolean isInstanceOf(final Object clazz) { if (clazz instanceof JSObject) { return ((JSObject) clazz).isInstance(this); } return false; } @Override public String getClassName() { return getClass().getName(); } /** * @implSpec This implementation always returns false */ @Override public boolean isFunction() { return false; } /** * @implSpec This implementation always returns false */ @Override public boolean isStrictFunction() { return false; } /** * @implSpec This implementation always returns false */ @Override public boolean isArray() { return false; } /** * Returns this object's numeric value. * * @return this object's numeric value. * @deprecated use {@link #getDefaultValue(Class)} with {@link Number} hint instead. */ @Override @Deprecated public double toNumber() { return JSType.toNumber(JSType.toPrimitive(this, Number.class)); } /** * Implements this object's {@code [[DefaultValue]]} method. The default implementation follows ECMAScript 5.1 * section 8.6.2 but subclasses are free to provide their own implementations. * * @param hint the type hint. Should be either {@code null}, {@code Number.class} or {@code String.class}. * @return this object's default value. * @throws UnsupportedOperationException if the conversion can't be performed. The engine will convert this * exception into a JavaScript {@code TypeError}. */ public Object getDefaultValue(final Class<?> hint) { return DefaultValueImpl.getDefaultValue(this, hint); } /** * When passed an {@link AbstractJSObject}, invokes its {@link #getDefaultValue(Class)} method. When passed any * other {@link JSObject}, it will obtain its {@code [[DefaultValue]]} method as per ECMAScript 5.1 section * 8.6.2. * * @param jsobj the {@link JSObject} whose {@code [[DefaultValue]]} is obtained. * @param hint the type hint. Should be either {@code null}, {@code Number.class} or {@code String.class}. * @return this object's default value. * @throws UnsupportedOperationException if the conversion can't be performed. The engine will convert this * exception into a JavaScript {@code TypeError}. */ public static Object getDefaultValue(final JSObject jsobj, final Class<?> hint) { if (jsobj instanceof AbstractJSObject) { return ((AbstractJSObject) jsobj).getDefaultValue(hint); } else if (jsobj instanceof JSONListAdapter) { return ((JSONListAdapter) jsobj).getDefaultValue(hint); } return DefaultValueImpl.getDefaultValue(jsobj, hint); } }